Foot-and-mouth Disease Vaccine Research Articles

Enhanced stability of foot-and-mouth disease vaccine antigens with a novel formulation

The structural instability of inactivated Foot-and-mouth disease virus antigen hinders the development of vaccine industry. The use of an inexpensive, biocompatible formulation to slow down the degradation of antigen would address the problem. Here, phosphate-buffered saline (PBS) was showed to be effective in stabilizing 146S and hence determined as basic solution buffer. Excipients such as trehalose, sucrose, arginine, cysteine, calcium chloride, BSA and ascorbic acid were found to protect 146S from massive structural breakdown. Using orthogonal test, we confirmed the novel formulation as a combination of 5% (w/v) trehalose, 5% (w/v) sucrose, 0.05 M arginine, 0.01 M cysteine, 0.01 M calcium chloride, 1% (W/V) BSA and 0.001 M ascorbic acid in PBS. The formulation increased vaccine stabilization, with retention rate of 14% after storage at 4 °C for 14 months. Particle size for vaccine was at approximately 220 nm and physicochemical detecting findings were rarely abnormal in morphology and emulsion type. In summary, these results revealed that the novel formulation is beneficial to make the FMD vaccine more stable and effective, reducing the dependence on cold storage and delivery.

Bovine Foot-and-Mouth-Disease risk factors in Mymensingh district of Bangladesh

Background: A hospital-based case-control study was undertaken to identify the risk factors for bovine Foot-and-Mouth-Disease (FMD) in the Mymensingh district of Bangladesh. Methods: Two hundred and eighteen FMD cases diagnosed between 2009 and 2018 at the Bangladesh Agricultural University Veterinary Teaching Hospital (BAUVTH) were selected and three controls per case were then selected from BAUVTH (n=872). Data on age, breed, gender, location, and time of presentation were used for the analysis. A multivariable mixed-effect logistic regression model was used to identify risk factors. Location was considered random intercept, demographic variables, and season as fixed effects. Results: The lowest (10) and highest (43) cases were recorded in 2014 and 2015, respectively. There was a decreasing trend (τ = -0.07) in FMD occurrence but was inconsistent and statistically insignificant (P=0.85). The odds FMD was significantly higher in cattle aged >1–3 years (odds ratio (OR) 2.3; 95% confidence interval (CI): 1.5; 3.6) and >3–8 years (OR 1.9; 95% CI: 1.3; 3.0) compared to those aged ≤ 1years. Indigenous cattle (OR 1.7; 95% CI: 1.1; 2.8) were at higher risk of being an FMD case than Shahiwal cross. In addition FMD cases were significantly higher in pre-monsoon (OR 1.9; 95% CI: 1.3; 2.9) and winter (OR 2.2; 95% CI: 1.3; 3.7) than post-monsoon season. Conclusion: Indigenous cattle aged between >1 year to 8 years should be prioritized for FMD vaccination, especially before pre-monsoon and winter seasons to prevent future FMD outbreaks and control FMD in Bangladesh.

Antiviral effect of vesatolimod (GS-9620) against foot-and-mouth disease virus both in vitro and invivo

Foot-and-mouth disease (FMD) is an acute contagious disease of cloven-hoofed animals such as cows, pigs, sheep, and deer. The current emergency FMD vaccines, to induce early protection, have limited use, as their protective effect in pigs does not begin until 7 days after vaccination. Therefore, the use of antiviral agents would be required for reducing the spread of foot-and-mouth disease virus (FMDV) during outbreaks. Vesatolimod (GS-9620), a toll-like receptor 7 agonist, is an antiviral agent against various human disease-causing viruses. However, its antiviral effect against FMDV has not been reported yet. The aim of this study was to investigate the antiviral effects of GS-9620 against FMDV both in vitro and in vivo. The inhibitory effect of GS-9620 on FMDV in swine cells involved the induction of porcine interferon (IFN)-α and upregulation of interferon-simulated genes. Protective effect in mice injected with GS-9620 against FMDV was maintained for 5 days after injection, and cytokines such as IFN-γ, interleukin (IL)-12, IL-6, and IFN-γ inducible protein-10 could be detected following the treatment with GS-9620. Furthermore, the combination of GS-9620 with an FMD-inactivated vaccine was found to be highly effective for early protection in mice. Overall, we suggest GS-9620 as a novel and effective antiviral agent for controlling FMDV infection.

The C3d-fused foot-and-mouth disease vaccine platform overcomes maternally-derived antibody interference by inducing a potent adaptive immunity

Vaccination prevents and controls foot-and-mouth disease (FMD). However, the current FMD vaccine remains disadvantageous since it cannot overcome maternally-derived antibody (MDA) interference in weeks-old animals, which suppress active immunity via vaccination. To address this, we developed the immune-enhancing O PA2-C3d and A22-C3d FMD vaccine strains that can stimulate receptors on the surface of B cells by inserting C3d (a B cell epitope) into the VP1 region of O PA2 (FMDV type O) and A22 (FMDV type A). We purified inactivated viral antigens from these vaccine strains and evaluated their immunogenicity and host defense against FMDV infection in mice. We also verified its efficacy in inducing an adaptive immune response and overcome MDA interference in MDA-positive (MDA(+), FMD-seropositive) and -negative (MDA(−), FMD-seronegative) pigs. These results suggest a key strategy for establishing novel FMD vaccine platform to overcome MDA interference and induce a robust adaptive immune response.

Determination of TCID50 of O, A, Asia-1 serotypes foot-and-mouth disease virus to the production of trivalent vaccine in bioreactor

This research work was designed to ensure the production of quality Foot and Mouth Disease (FMD) vaccine. For ensuring the standard quality of vaccine, it is important to propagate the FMD Virus (FMDV) into the cell line. Tissue Culture Infective Dose50 (TCID50) assay was used to determine the biological titer of FMD virus serotypes. Baby Hamster Kidney-21 (BHK-21) Monolayer cell and BHK-21 Clone 13 Suspension cell were used to determine the TCID50 of FMDV. The result for calculating TCID50 under Monolayer cell showed that the highest biological titer of O, A, Asia-1 serotype were 10-9.83/ml, 10-9.36/ml and 10-9.70/ml respectively. On the other hand, the result for calculating TCID50under BHK-21 Clone 13 suspension cell of O, A, Asia-1 serotypes were10-6.66\ml,10-6.50\ml and 10-6.50/ml respectively. BHK-21 cell line, either the monolayer or the suspension cell culture system were used in FMD vaccine production to ensure the potency and the quality of the vaccine to be produced.BHK-21 monolayer cell sub-cultured by applying roller cell culture cultivation system and BHK-21 clone 13 suspension cell sub-cultured by using suspension cell culture cultivation system. Suspension culture of BHK-21 cells allows large-scale virus propagation and cost-efficient vaccine production by using Bioreactor with capacity of 50 liters maintaining biosafety and biosecurity. Asian J. Med. Biol. Res. 2022, 8 (2), 63-68

Factors Involved in Removing the Non-Structural Protein of Foot-and-Mouth Disease Virus by Chloroform and Scale-Up Production of High-Purity Vaccine Antigens.

Foot-and-mouth disease (FMD) is an economically important and highly infectious viral disease, predominantly controlled by vaccination. The removal of non-structural proteins (NSPs) is very important in the process of FMD vaccine production, because vaccinated and naturally infected animals can be distinguished by the presence of NSP antibodies in the FMD serological surveillance. A previous study reported that 3AB protein, a representative of NSPs, was removed by chloroform treatment. Therefore, in this study, the causes of 3AB removal and factors affecting the effect of chloroform were investigated. As a result, the effectiveness of chloroform differed depending on the virus production medium and was eliminated by detergents. In addition, it was found that 3AB protein removal by chloroform is due to the transmembrane domain of the N-terminal region (59–76 amino acid domain). Further, industrial applicability was verified by applying the chloroform treatment process to scale-up FMD vaccine antigen production. A novel downstream process using ultrafiltration instead of polyethylene glycol precipitation for high-purity FMD vaccine antigen production was established. This result will contribute toward simplifying the conventional process of manufacturing FMD vaccine antigens and ultimately reducing the time and cost of vaccine production.

Evaluation of foot and mouth disease (FMD) vaccine using registered surveillance data.

Foot and mouth disease (FMD) is a highly contagious transboundary disease of cloven-hoofed animals. In Iran, the disease is endemic with outbreaks occurring throughout the year. Mass vaccination of domestic ruminants has been adopted as a preventive strategy. A study was conducted to evaluate the effectiveness of currently in use FMD vaccines using official disease surveillance data. Surveillance data of FMD outbreaks and vaccination in cattle farms from January 2017 to March 2019 was obtained from the Iranian Veterinary Organization (IVO). A case-control study comprising 190 laboratory-confirmed cases and 380 randomly selected controls, frequency-matched by location and production type, was performed to estimate vaccine effectiveness (VE) of vaccines in industrial and semi-industrial farms. Multivariable logistic regression was used to estimate odds ratios based on brand of vaccine, time since vaccination, and within-farm vaccination coverage. A total of 2297 outbreaks occurred during the study period with majority (75%) reported from village epi-units. Only 38% of industrial and semi-industrial farms recorded vaccination during the studied period. Vaccination was effective against clinical disease with the highest VE observed in farms vaccinated with commercial vaccine brand A (VE = 0.90%, 95% CI 0.79-0.96), vaccinating > 94% of herd population (VE = 0.77%, 95%CI 0.54-0.98) and in < 35days after vaccination (VE = 0.56%, 95% CI 0.04-0.8). The current high-potency vaccines confer medium protection in investigated cattle farms. The high occurrence of the disease in village epi-units and low coverage of vaccination in industrial and semi-industrial farms will contribute to maintenance and circulation of the virus in the susceptible population.

Biodegradable Imiquimod-Loaded Mesoporous Organosilica as a Nanocarrier and Adjuvant for Enhanced and Prolonged Immunity against Foot-and-Mouth Disease Virus in Mice.

Foot-and-mouth disease (FMD), a serious, fast-spreading, and virulent disease, has led to huge economic losses to people all over the world. Vaccines are the most effective way to control FMD. However, the weak immunogenicity of inactivated FMD virus (FMDV) requires the addition of adjuvants to enhance the immune effectiveness of the vaccines. Herein, we formulated and fabricated biodegradable dendritic mesoporous tetrasulfide-doped organosilica nanoparticles SOMSN with imiquimod complex (SOMSN-IMQ) and used it as a platform for FMD vaccine delivery and as an adjuvant. SOMSN-IMQ demonstrated excellent stability for 6 months when stored in PBS, while it could be completely degraded within 42 days in SBF at room temperature. Biosafety experiments such as cell toxicity, hemolysis, and histology indicated that the as-prepared SOMSN-IMQ showed nontoxicity and good biocompatibility. Furthermore, SOMSN-IMQ exhibited a maximum adsorption capacity of 1000 μg/mg for inactivated FMDV antigens. Our results showed that SOMSN-IMQ can be effectively engulfed by RAW264.7 cells in a dose-dependent manner. After immunization, SOMSN-IMQ@FMDV can elicit persistent higher antibody levels, higher IgG2a/IgG1 ratio, and cytokine expression, which indicated that SOMSN-IMQ@FMDV triggered superior humoral and cellular immune responses. Moreover, SOMSN-IMQ could provoke maturation and activation of dendritic cells in lymph nodes (LDCs) as well as the proliferation of lymphocytes in vivo. Thus, SOMSN-IMQ could promote effective and potent immunity and provide a promising adjuvant platform for FMDV vaccination with acceptable safety.

Preparation of a polysaccharide adjuvant and its application in the production of a foot-and-mouth disease virus-like particles vaccine

Foot-and-mouth disease (FMD) virus-like particles (VLPs) comprise a new and effective FMD vaccine, which often requires the addition of adjuvants to induce a vigorous immune response in order to protect livestock from the challenge of FMD virus (FMDV). Oil emulsion delivery systems have been developed and used widely in the field of veterinary vaccines because of their low cost, slow release, and efficient antigen protection. In this study, we designed and synthesized an optimized Achyranthes bidentata polysaccharide (ABP) delivery system (ABPOA) based on a pseudo-ternary phase diagram. We systematically evaluated the stability, biocompatibility, and immunological effects of the ABP delivery system. The results demonstrated that ABPOA is a stable adjuvant delivery system and capable of long-term storage at 37 °C for up to 6 months. ABP-VLPs can be effectively stored for long periods when ABPOA is used as the delivery system for VLPs. Importantly, guinea pig-specific antibodies were significantly increased within 28 days when ABPOA was used as a delivery system, thereby promoting the proliferation of splenic lymphocytes. In addition, immunization with one dose of ABP-VLPs resulted in complete protection from homologous FMDV challenge in guinea pigs. Therefore, the polysaccharide oil emulsion adjuvant comprising ABPOA effectively improved the immunogenicity of FMD-VLPs. These findings provide a theoretical basis for the preparation of oil emulsion adjuvants for veterinary vaccines.

BacMam Expressing Highly Glycosylated Porcine Interferon Alpha Induces Robust Antiviral and Adjuvant Effects against Foot-and-Mouth Disease Virus in Pigs.

Foot-and-mouth disease (FMD) is an acute contagious disease that affects cloven-hoofed animals and has severe global economic consequences. FMD is most commonly controlled by vaccination. Currently available commercial FMD vaccines contain chemically inactivated whole viruses, which are thought to be slow acting as they are effective only 4 to 7 days following vaccination. Hence, the development of a novel rapid vaccine or alternative measures, such as antiviral agents or the combination of vaccines and antiviral agents for prompt FMD virus (FMDV) outbreak containment, is desirable. Here, we constructed a recombinant baculovirus (BacMam) expressing consensus porcine interferon alpha (IFN-α) that has three additional N-glycosylation sites driven by a cytomegalovirus immediate early (CMV-IE) promoter (Bac-Con3N IFN-α) for protein expression in mammalian cells. Bac-Con3N IFN-α expressing highly glycosylated porcine IFN-α protein increased the duration of antiviral effects. We evaluated the antiviral effects of Bac-Con3N IFN-α in swine cells and mice and observed sustained antiviral effects in pig serum; additionally, Bac-Con3N IFN-α exhibited sustained antiviral effects in vivo as well as adjuvant effects in combination with an inactivated FMD vaccine. Pigs injected with a combination of Bac-Con3N IFN-α and the inactivated FMD vaccine were protected against FMDV at 1, 3, and 7 days postvaccination. Furthermore, we observed that in combination with the inactivated FMD vaccine, Bac-Con3N IFN-α increased neutralizing antibody levels in mice and pigs. Therefore, we suggest that Bac-Con3N IFN-α is a strong potential antiviral and adjuvant candidate for use in combination with inactivated FMD vaccines to protect pigs against FMDV. IMPORTANCE Early inhibition of foot-and-mouth disease (FMD) virus (FMDV) replication in pigs is highly desirable as FMDV transmission and shedding rates are higher in pigs than in cattle. However, commercial FMD vaccines require at least 4 to 7 days postvaccination (dpv) for protection, and animals are vulnerable to heterologous viruses before acquiring high antibody levels after the second vaccination. Therefore, the development of antiviral agents for use in combination with FMD vaccines is essential. We developed a novel antiviral and immunostimulant, Bac-Con3N IFN-α, which is a modified porcine IFN-α-expressing recombinant baculovirus, to improve IFN stability and allow its direct delivery to animals. We present a promising candidate for use in combination with inactivated FMD vaccines as pigs applied to the strategy had early protection against FMDV at 1 to 7 dpv, and their neutralizing antibody levels were higher than those in pigs administered the vaccine only.

Development of swine Fc conjugated Serotype O Foot and mouth disease virus like particles

Abstract Foot-and mouth disease virus (FMDV) cause a highly contagious infection in cloven-hoofed animals. The current conventional FMD vaccines are produced by chemical inactivated virulent FMDV virions, but conventional FMD vaccines risky and limitation such as respect to accidental release of FMDV and high-level biosafety facilities were required to handle FDMV. FMDV virus like particle (VLP) could be alternative choice for future vaccine against FMDV because of efficacy and safety. Receptor for Fc portion of antibody play and important role in the activation of immune response for infection of virus and bacteria. Therefore, immunization with a complex of virus antigen and Fc has the potential to be an improved. Here we report our vaccine studies with Fc conjugated serotype O FMDV VLP for alternative FMDV vaccine.

Epidemiological and clinical characteristics of the foot and mouth disease outbreaks in cattle in central Ethiopia

Foot and mouth disease (FMD) is an acute highly contagious viral disease of all cloven-hoofed animals that causes significant economic problems in Ethiopia. The objectives of this study were to assess the morbidity and clinical features of FMD in sick cattle and identify causal serotypes of FMD outbreaks in central Ethiopia. Outbreaks of FMD were investigated in a total of 150 herds of cattle from January 2021 to April 2021. Seven epithelial tissue and 23 oral swab samples were collected and subjected to a real-time polymerase chain reaction (rRT-PCR) and Sandwich Enzyme-linked Immunosorbent Assay (ELISA) for detection and serotyping of FMD virus, respectively. A total of 150 herds of cattle were examined, of which 114 (76%) herds of cattle were clinically affected with FMD. In this study, 75.9% animal-level morbidity was recorded. Exotic breeds and adult cattle were more affected by Foot and Mouth Disease Virus (FMDV) with morbidity of 100% and 77.4%, respectively. The clinical features in sick cattle showed that profuse salivation was the most frequently observed clinical sign (40%) followed by oral cavity vesicle formation (30%), and interdigital space lesion (15%). Out of 30 samples subjected to rRT-PCR and ELISA test, 28 (93.33%) and 27 (90%) samples were found positive, respectively. In this study, three types of FMD serotypes were detected in which SAT-2 (n = 13) was the predominant serotype followed by serotype O (n = 9), and serotype A (n = 5). The current study revealed that FMD serotype SAT-2 was highly responsible for the occurrence of FMD outbreaks in central Ethiopia. Although the FMD vaccine produced in Ethiopia contains all the identified serotypes, detailed studies on topotypes identification have to be performed to provide full protection.

Age-Dependent Dynamics of Maternally Derived Antibodies (MDAs) and Understanding MDA-Mediated Immune Tolerance in Foot-and-Mouth Disease-Vaccinated Pigs.

Vaccine-induced active immunity in young animals may be compromised via interference caused by maternally derived antibodies (MDAs). Since the level, titer, and half-life of MDAs vary per individual, it is difficult to determine the appropriate timing of foot-and-mouth disease (FMD) vaccination in the field. In order to better understand the age-dependent characteristics of MDA in sows and piglets as well as the phenomenon of reduced vaccine-mediated active immunity due to MDAs, this study sought to determine antibody titers through structural protein (SP) O, A ELISA analyses, and virus-neutralizing (VN) antibody titers as well as their half-lives in the sera of sows and piglets derived from FMD-vaccinated mother. Furthermore, immunoglobulin (Ig) subtypes, such as IgG, IgM, and IgA, in serum were also evaluated. To understand the correlation between the inhibition of vaccine-mediated active immunity by MDA-mediated passive immunity and regulatory T (Treg) cells, Treg-related cytokine levels were explored. Our findings will help to predict the optimal timing of vaccination for overcoming MDAs and inducing a robust vaccine-mediated immune response in young individuals vaccinated against FMD. They also add to our understanding of MDA characteristics and interference, providing insight for the development of innovative strategies and novel FMD vaccine for overcoming such interference.

Effect of the Faradarmani Consciousness Field on immune response induced by an inactivated vaccine against Foot and Mouth disease virus (FMDV) in rats and replication of FMDV in vitro

Foot-and-mouth disease (FMD) is one of the highest risk factors affecting the animal industry throughout the world. Currently, available commercial FMD vaccines have numerous limitations, such as slow induction and short-term maintenance of antibody titers. Therefore, a novel approach is needed that can induce high neutralizing antibody titers to protect the host in the early stages of FMD virus (FMDV) infection and maintain high antibody titers for long periods after one vaccination dose. There are several T-Consciousness Fields (TCFs), introduced by Mohammad Ali Taheri. TCFs are not matter or energy, so they cannot be measured directly. However, we can evaluate their effects indirectly through several reproducible experiments in the laboratory. The present study aimed to evaluate the effect of Faradarmani CF as a type of the TCFs on FMDV replication, titer, and RNA copy number as well as the humoral immune response against two types of inactivated FMDV vaccines with different adjuvants in rats. Two types of FMD vaccines with different adjuvants (Freund and Alum) were prepared, and then 30 male Wistar rats were immunized with vaccines. Rats were divided into 6 groups (n=5 per group). Four groups of rats were studied using the different combinations of treatments and two groups served as positive and negative controls. Vaccination intervals were every 14 days three times. Serum neutralization test (SN) and Enzyme-linked immunosorbent assay (ELISA) were used to assess changes in antibody levels in the serum samples of rats after each immunization. The results showed that Faradarmani CF induced the replication of the virus in vitro. In addition, antibody levels in treated groups under both Freund adjuvant and Alum adjuvant vaccines increased significantly compared to groups without Faradarmani CF treatment. In conclusion, our data suggest that Faradarmani CF may provide an effective approach to increase the success of immunization and vaccination against FMDV serotype O. It is recommended that the effects of TCFs on different types of vaccines be investigated.

Foot and mouth disease prevalence in cattle and buffaloes from India determined by systematic review and meta-analysis

In the present study, Foot and Mouth Disease (FMD) prevalence in cattle and buffaloes from India was determined by employing systematic review and meta-analysis. The FMD prevalence studies (73) reported during 1986-2021 were obtained from online databases, offline literatures and meta-analysis by using meta package in R-Software was done. The pooled FMD prevalence in India was 43% (95% level CI 35-52%, PI 3-94%) obtained by using 5,00,267 samples. Period-wise analysis revealed a higher prevalence of 68% during 1986-2000 than recent years. A higher FMD prevalence in east zone (59%), and lower in central zone (24%) was observed. Among 19 states, a higher prevalence of FMD was detected in Rajasthan (81%) and lower in Andaman and Nicobar (3%). Species-wise analysis indicated a higher prevalence in cattle (45%) than buffaloes (30%). The method-wise analysis revealed a higher prevalence in antigen detection (49%) than the antibody detection (42%) methods. The FMD seroprevalence was 59% against the FMD vaccination obtained by liquid phase blocking ELISA. In India, a higher FMD prevalence by serotype O (64%) than other serotypes was observed. Thus, the higher FMD prevalence zone, states, species, methods and serotypes identified may be employed by policy makers for making informed decisions to maximise the use of scarce resources available. There was a decreasing trend in FMD prevalence in the recent years, however, need is there to prevent FMD by vaccination to move in the progressive control pathway stages. This will help in increasing export trade and eventually result in economic benefits to dairy farmers

The effects of simultaneous foot-and-mouth disease and Escherichia coli vaccination on the immunity of pregnant cows and their calves

Fighting against infectious diseases with almost 18 million cattle spread over a wide geographical area is troublesome economically and physically. The administration of different vaccines simultaneously during the foot-and-mouth disease (FMD) vaccination campaign will help reduce both the vaccine stress of animals and the field veterinarians’ workload. Diarrhea due to Escherichia coli (E. coli) is a significant problem and a major cause of mortality in calves, and thus, simultaneous application of FMD and E. coli vaccines to dams would prove efficient in field conditions. This study aimed to investigate the effect of simultaneous administration of four different locally produced gel and oil adjuvant inactivated E. coli vaccines with locally produced oil adjuvant inactivated FMD vaccine on neutralizing antibody levels and the properties of the antibodies in late-term pregnant dams and their calves. For this purpose, seven to eight-month-old pregnant dams (n = 146) were divided into two main groups to receive two doses (single and booster), or only single dose (no booster). FMD neutralizing antibody titers were evaluated by a virus neutralization test against serotype A, O, and Asia1. In addition, the properties of antibodies against serotype A were assessed by isotype and avidity ELISAs. E. coli antibodies were measured by the hemagglutination inhibition test. Results of the study revealed no safety problems in any dams after the vaccinations. On day 42, calves of the dams vaccinated simultaneously had higher neutralizing antibody titers against three serotypes than the calves of only FMD vaccinated dams. IgG1/IgG2 ratio was higher in single-dose groups than booster-dose groups against serotype A in calves. The avidity index was detected over the threshold value (24.5%). A positive correlation was found in the transmission of maternal antibodies from mothers to calves in simultaneous administration groups. In conclusion, during the FMD vaccine campaigns, FMD and E. coli vaccines can be simultaneously applied to dams in the 7th and 8th months of gestation. Results of this study has led to the inclusion of simultaneous application of FMD and E. coli vaccines in the ‘Animal Disease and Animal Movement Control Program-2018′ and these two vaccines have been applied in the field ever since as a solution for field veterinarians to save time and labor during vaccination.

¿Debemos dejar de vacunar contra Fiebre Aftosa en Uruguay? Una encuesta nacional a veterinarios Autores/as

Veterinarians’ opinions are key to successfully implementing disease control programs. Foot-and-mouth disease (FMD) has a significant economic impact due to animal production losses and trade restrictions. In 2010, PANAFTOSA defined a roadmap to FMD eradication in South America. Although Uruguay has implemented this plan by using mandatory vaccination since the last outbreak in 2001, vaccination restricts access to premium export markets. The objective of this study was to determine the perception of veterinarians involved in large animal disease control programs (accredited veterinarians) on a future FMD control stage without vaccination in Uruguay. Two hundred and fifty-six accredited veterinarians were surveyed between August and September 2018. Two strata were defined as follows: Stratum 1 (pre-FMD outbreak), veterinarians who enrolled in the University of the Republic in Uruguay before or in 2001 (N=708), and Stratum 2 (post-FMD outbreak) veterinarians who enrolled after 2001 (N=426). Data related to demographics, vaccination perceptions, and FMD experience were collected through online and phone interviews. Logistic regressions were used to determine the association between demographic variables, FMD-related risk perceptions, and the willingness to stop FMD vaccination. 41.7% (±&nbsp;4.2) and 29.4% (±&nbsp;4.2) of veterinarians, for strata 1 or 2, respectively, were willing to stop vaccination. Veterinarians’ geographical region of work influenced this perception. The northeast area being more likely to support stopping vaccination (46.3&nbsp;±&nbsp;5.8%) when compared to the South-center (39.2&nbsp;±&nbsp;4.9%) and West (25.3&nbsp;±&nbsp;5.0%). Accredited veterinarians are still hesitant to stop vaccination, presenting problems when implementing a non-vaccination stage.

Molecular detection of foot and mouth disease virus serotype A in goats (Capra hircus)

Foot and mouth disease (FMD) is a highly contagious, transboundary, and re-emerging viral disease that mostly affects cloven-hoofed animals specially cattle, goats, swine, sheep, etc. resulting in significant economic losses. Despite regular vaccination, outbreaks of the disease have become a yearly occurrence across the country. RT-PCR was used to determine the prevalence and molecular detection of serotype A of FMDV in clinically affected goats in Goat research farm, BLRI, Savar, Dhaka, Bangladesh during August 2018. A total of 9 samples were taken from 1 to 2 years old Black Bengal goats suspected to have FMD. FMDV was detected in 55.56% (5/9) of the suspected samples using RT-PCR. The serotype of positive samples was also determined using gsRT-PCR. However, FMDV serotype A was prevalent in 100% (5) positive samples. Additionally, considering the age, the prevalence of confirmed FMD outbreak was 40% (2), 40% (2), and 20% (1) at the age of 1, 1.5 and 2 years, respectively. It was found that young goats are more susceptible to FMDV than adults. However, it can be concluded that suspected goats were infected with FMDV serotype A and trivalent FMD vaccine is suggested for prevention and control of FMD outbreak. Asian J. Med. Biol. Res. 2022, 8 (1), 30-36

Avidity of Polyclonal Antibodies to Foot-and-Mouth Disease Virus in Bovine Serum Measured Using Bio-Layer Interferometry.

Foot-and-mouth disease (FMD) is a disease of cloven-hoofed livestock caused by FMD virus (FMDV). FMD can be controlled through the use of inactivated vaccines, and it is well established that the protection afforded by FMD vaccines correlates strongly with neutralising antibody titres. However, the overall strength of binding, referred to as avidity, is also an important parameter with respect to the ability of antibodies to neutralise virus infection, and there is evidence that avidity can affect the level of protection afforded by FMDV vaccines. Here, as an alternative to modified enzyme-linked immunosorbent assays (avidity ELISAs) incorporating a chaotropic wash step, we used bio-layer interferometry (BLI) to measure the avidity of bovine polyclonal antibodies against FMDV capsids. We conducted preliminary experiments using recombinant FMDV capsids, as well as peptides representing antigenic loops, to demonstrate that the binding of monoclonal antibodies targeting specific antigenic sites could be detected using BLI. Subsequent experiments using polyclonal sera derived from FMD vaccinated cattle provided evidence of a positive correlation between the neutralising titre of the serum and the avidity as measured by BLI. Furthermore, we observed an increase in BLI avidity, as well as in the titre, in vaccinated animals upon challenge with the live virus.

Improved vaccination protocol to enhance immunity in lambs of Kuwait farms

The susceptibility of lambs to infective diseases should be minimized by improving the immunity of lambs through effective vaccination procedures to abate lamb mortality in sheep farms. In this regard, field experiments were carried out with 180 pregnant ewes of Naeemi sheep breed at the PAAFR (Public Authority for Agriculture and Fisheries Research Station, Kuwait). The results revealed that the concentration of serum Ig’s in blood samples collected from ewes vaccinated during pregnancy with Pasteurella, Clostridia, FMD (Foot and Mouth Disease) and PPR (Peste des Petits Ruminants) vaccines was significantly elevated as vaccination against these four diseases agents would have ultimately resulted in circulating antibodies protecting the animals against natural exposure. Theconcentration of colostral Ig’s produced by vaccinated ewes during the pregnancy period was significantly (P<0.05) higher than the normal colostrum secreted from unvaccinated ewes during pregnancy, ensuring the positive role of the colostrum in transferring passive immunity. The results clearly illustrated no cases of mortality and abortion, as vaccination has played a role in maintaining the health of ewes by overcoming the targeted pathogens and preventing any abnormalities in the pregnant ewes. The present study confirmed the improved immune status of young lambs born to ewes vaccinated twice during pregnancy, reflecting improved health status. It is recommended to maintain 21 days’ intervals in vaccinating ewes with different vaccines for specific diseases.